Fiberglass Supply Depot Wax Additive - 4 oz Surfacing Agent for use with Gelcoat and Polyester resins

Fiberglass Supply Depot Wax Additive - 4 oz Surfacing Agent for use with Gelcoat and Polyester resins

• Creates a tack-free surface: Wax additives mixed into gelcoat help eliminate the sticky surface caused by air exposure, allowing the gelcoat to cure fully and be sanded or polished once cured
• Used only in final/top coats: Add the wax additive only to the final gelcoat layer (or final polyester resin layer) — do not add to intermediate layers that need bonding.
• How it works: The wax (often paraffin or styrene-based) migrates to the surface during cure, forming a thin barrier that blocks oxygen and lets the resin cure hard all the way to the surface.
• Dosage matters: Typical ratios are around 1 oz per quart or ~4 oz per gallon of gelcoat — too much can cause defects like “fish eyes” or uneven finish.
• Catalyst still required: Wax additive doesn’t replace hardener — you still must add the correct amount of MEKP catalyst to gelcoat for polymerization to occur.
• Terminology: These products are often called wax additive, surfacing agent, or surface seal for gelcoat/polyester resin.